Electronic components, and notably power transistors, are generally marketed in a straight-lead version. These components are suited to conventional mounting on an electronic card. A certain number of power transistors are also available in a bent-lead version, particularly suited to surface mounting. These components are generally referred to as surface-mounted components (SMC). Surface mounting is particularly advantageous in that it allows the appropriate components to be assembled automatically on their card, and consequently helps to reduce the industrialization and marketing cost.
Now, not all components are available in a bent-lead version. Few power microwave components, particularly transistors rated at over 100 W are suitable for surface mounting. Many mass-produced components are therefore not originally designed for surface mounting.
Furthermore, compared to the straight-lead versions, the performance of components (notably radio frequency and microwave components) with bent leads reduces when the usage frequency increases. In practice, the bent leads, because of their shape, impose a spurious inductance unlike the same component with straight leads. For a power transistor, this spurious inductance tends to reduce the gain and the instantaneous bandwidth of the circuit that uses it.